Self-Healing Waterborne Polyurethane Elastomers Based on Multiple Reversible Bonds with Good Mechanical Performance for Composite Conductors

As a functional material, polyurethane elastomers have a wide range of applications in fields such as flexible wearable devices and healthcare but are prone to damage during use. As a result, they are often incorporated with self-healing properties to prolong their service life. The preparation of polyurethane elastomers with excellent mechanical and self-healing properties has become crucial to addressing this issue. In this study, a new self-healing system with excellent mechanical properties is developed by reacting butanedione oxime (DMG) and gallic acid (GA) with isocyanate (─NCO) to introduce oxime-carbamate bonds and phenol-carbamate bonds into waterborne polyurethane. The triple dynamic reversible synergistic network formed through multiple reversible covalent bonds and hydrogen bonds enhances the mechanical and self-healing properties of the waterborne polyurethane elastomers. The results demonstrate that the synthesized polyurethane elastomer films exhibit excellent mechanical properties (strength of 41.02 MPa, elongation at break of 955.9%, toughness of 112.17 MJ m⁻³) and self-healing properties (healing efficiency of 91.21%). In addition, the composite conductor (DG-WPU-CNTs) prepared by incorporating this polyurethane elastomer with carbon nanotubes (CNTs) exhibits excellent sensitivity, stability, and self-healing properties, providing a basis for its application in flexible wearable devices.